The present invention relates to conjugating unconjugated unsaturation of lipoidal feedstock and in particular to such process practiced on fatty acids or esters thereof using the sulfided nickel catalyst.
British Pat. No. 646,919 proposes to conjugate unconjugated unsaturation contained in glyceride oils by heating the oils to about 170.degree.-220.degree. C. in the presence of 1 to 5% of sulfided nickel or sulfided cobalt catalyst while bubbling an inert gas such as carbon dioxide through the oil during the process. Similarly, British Pat. No. 693,981 and its corresponding U.S. Pat. No. 2,692,886 propose to conjugate unconjugated fatty acids or esters thereof at a temperature of less than 140.degree. C., advantageously 100.degree.-120.degree. C., in the presence of about 5 to 10% of nickel or cobalt catalyst containing nickel silicate or cobalt silicate and about 1 to 10% sulfur by weight of the nickel or cobalt. This conjugation process also is conducted under an inert gas blanket or in vacuo.
The present invention is directed to the use of a sulfided nickel catalyst to conjugate fatty acids or esters thereof while maintaining a low positive hydrogen pressure in the system.